Conventionally, a plurality of load devices mounted in a vehicle operate based on power that is supplied from a battery. At the time of power supply failure due to malfunction or voltage reduction of the battery, operation of the respective load devices is no longer guaranteed. Thus, a power-supply system that determines a short-circuit abnormality of a battery based on a terminal voltage of that battery has been proposed (e.g., see JP 2011-111032A).
Incidentally, it is conceivable to employ a power-supply system that is provided with a plurality of batteries (e.g., main battery and sub-battery), and that supplies power to a load device from the sub-battery at the time of malfunction or voltage reduction of the main battery. The plurality of batteries are connected to the load device by one connector. Thus, there is risk of a short-circuit fault occurring between the paths through which power is supplied from the plurality of batteries to the load device. In a power-supply system that detects a short-circuit abnormality based on the terminal voltage of a battery such as abovementioned, it is difficult to detect a short-circuit fault between the paths.
The present invention was made in order to solve the above problems, and an object thereof is to easily detect a short-circuit abnormality.